Hand cutting tool

ABSTRACT

This invention relates to a hand cutting tool especially applicable for cutting a taped layer from an insulated cable. The cutting tool comprises a pair of elongated lever members pivotally connected to each other intermediate their ends. The lever members include a pair of handles at one end and arched upper and lower jaws at the other end opposite the handles. A spring wire having a looped portion therein is disposed between and connected to the upper and lower jaws.

United States Patent 1151 3,665,602

Salahshourian 1 May 30, 1 972 541 HAND CUTTING TOOL 2,452,734 11/1948 Costelow ..30/91.1

[72] Inventor: l-looshang Salahshourian, Fan'field, Conn. Prim), Examiner Roben C- Riordon [73] Assignee: General Electric Company Assistant Examiner-J. C. Peters Attorney-R. Jonathan Peters, Philip L. Schlamp, Frank L. [22] Filed' 1971 Neuhauser, Oscar B. Waddell and Joseph B. Forman [21] Appl. No.: 123,984

[57] ABSTRACT U.S. invention relates to a cuttlng tool especially applica.

Int. Cl ..B26b 27/00 Field of Search ..30/90.1, 116; 145/31; 8l/9.5 R, 9.5 A, 9.5 B

References Cited UNITED STATES PATENTS 3 Claims, 4 Drawing Figures PATENTEDMAY30 I972 3. 665.602

SHEEI 1 BF 2 Inven or A fforney Haas/mug 5a/ahs/1ourian PATENTEBMAY 30 I972 3. 665 602 SHEET 2 OF 2 i i liiiii l- In venfor Haas/1049 5a/a/1s/murz'an Afforney HAND CUTTING TOOL This invention relates to a hand cutting tool. In its more specific aspect, this invention relates to a hand tool for cutting the tape insulation of a cable.

In a typical high voltage cable, i.e., KV or higher, a semiconducting layer or tape is applied around the metal conductor, and an insulation layer is extruded over this surface. A ground shielding means is then concentrically disposed over the insulation, which usually comprises a semi-conducting tape and a metallic return shield. The semi-conducting tape, for example, may comprise a fabric web which has been coated with a plastic composition impregnated with carbon black. Useful semi-conducting tapes include nylon tape impregnated with carbon filled butyl or ethyl propylene rubber which has been cured, but other fabrics such as cotton or dacron and other coatings such as neoprene are also in common use. The structure may be further enclosed by a jacketing material such as polyvinyl chloride or a metallic jacket.

It is conventional in the cable industry to test high voltage cable for voids by an ionization level test. According to the test procedure, the ground shielding means is stripped back or unwound a short distance at each terminal to expose the insulation layer. The metal shield is connected to ground, and the semi-conducting tape is cut around its circumference. The cable termination may then be provided with a stress cone for testing in the mercury cup in oil or may be stress graded with a semi-conductive coating according to US. Pat. No. 3,396,231. According to the test procedure, voltage is applied to the cable and increased until ionization occurs. The voltage level at which ionization occurs in the cable coincides with the visual display on an oscilloscope or other suitable instrument. The termini are cut from the cable which, if found acceptable, is then shipped to the customer.

Quite obviously, in cutting the semi-conducting tape, it is essential that the underlying insulation layer not be nicked or scratched. Such scratches will result in a void thereby givlng a false ionization. Cutting is typically done with a knife which is a tedious and time-consuming task, and, notwithstanding the care exercised by the operator, scratches frequently occur.

This invention has as its purpose to provide hand cutting tool especially for cutting the tape in an insulated cable, and which overcomes the disadvantages of the prior art.

The invention, together with its objects and advantages, will be understood by referring to the following detailed specification, and to the accompanying drawings, in which:

FIG. 1 is a side view showing the hand cutting tool of the invention;

FIG. 2 is an exploded perspective view showing the parts of the tool of FIG. 1;

FIG. 3 is a perspective view of the hand cutting tool in operation showing a cable in place prior to cutting the tape; and

FIG. 4 is a further perspective view of the cutting tool inoperation showing the tape being cut.

In its broad concept, the hand cutting tool of the present invention, which is especially applicable for cutting a taped layer from an insulated cable, comprises a pair of elongated lever members which are pivotally connected to each other intermediate their ends. The lever members include a pair of handles at one end and arched upper and lowe jaws at the other end opposite the handles. A spring wire having a looped portion therein is disposed between and connected to the upper and lower jaws. When the handles are actuated the diameter of the loop is opened or closed.

Referring to the drawings, wherein like reference numerals designate similar parts throughout, there is shown in FIG. I the hand cutting tool of the present invention designated generally by the numeral 10. The tool includes a pair of lever members 12 and 14 having handles 16 and 18 and oppositely disposed upper and lower jaws 20 and 22. Lever member 14 is provided intermediate its ends with a semi-circular lug 23 having aligned apertures 24, which is suitably bifurcated to pivotally receive boss 25 depending from lever member 12intermediate its ends and having aperture 26. Pin 27, or some other suitable fastening means such as a bolt, extends through the apertures 24 and 26 of lug 23 and boss 26, respectively, for pivotally connecting the lever members 12 and 14.

Where desired, the handles are normally biased to an open position by any suitable means such as a spring bias. As shown here, handles 16 and 18 have oppositely aligned openings 28 and 29, and handle 16 is further provided with a relatively small opening 30 drilled through the handle at opening 28 and transverse thereto. A threaded attaching bolt 31 with circular head 32 having opening 33, extends through openings 28 and 29 so as to align openings 30 and 33 and pin 34 is passed through the aligned openings to connect bolt 31 to handle 16. The bolt is secured at the other end by locking nut 35. Spring 21 surrounds the bolt member and abuts the handles. In this manner the spring biases the handles to a normally open position.

Each jaw 20 and 22 is provided with oppositely disposed lateral bores 36 and 37. Spring wire 38, having a looped portion 39, disposed between the jaws, extends through the lateral bores and is connected at each end of the upper and lower jaws by threaded studs 40 and 42 having locking nuts 44 and 46.

In the preferred embodiment of the invention, spring wire 38 may be adjusted to vary the diameter of loop 39. Spring wire 38 extends at one end 38' beyond locking nut 46, and, by loosening this nut, the length of wire may be adjusted to vary the diameter of the loop 39 depending upon the cable size. After the diameter of the loop has been adjusted, the locking nut 46 is tightened to hold the wire in a fixed position. Insulated cable is manufactured in several different diameters, and therefore on cutting tool can be use for several cable sizes by simply adjusting the diameter of the loop.

It will be observed from FIG. 1 that when the cutting tool is at rest, it will assume the position shown by the solid lines. When force is applied to the handles 16 and 18, thereby closing the handles to the position shown by the dotted lines, the jaws 20 and 22 are actuated and loop 39 contracts. In this manner, the object within the loop is cut around its circumference.

FIGS. 3 and 4 further illustrate the hand cutting tool in operation. As illustrated, the tool is used to cut the semi-conducting tape wrapped over the primary insulation layer of a high power cable. The terminations of the cable, indicated generally by the numeral 48, to be tested for ionization are prepared according to the standard test procedure. As shown v in the drawings, the outer jacket 50 of the cable 48 is first stripped from thecable termination for a pre-determined distance, depending upon the test specifications. The metallic return shield such as copper tape 52 is unwound so as to expose the semi-conducting tape 54, and, for ionization testing, the end of the return shield is connected to ground (not shown). The end of the cable is then inserted through loop 39 to the position where it is desired to cut the semi-conducting tape. The operator holds in one hand the cutting tool and with the other hand unwinds the tape from the cable. When the handles of the cutting tool are closed the jaws are actuated and the loop contracts, thereby cutting the tape. The tape is simply unwound to the cutting edge thereby leaving expose insulation layer 56. The termination length may then be further prepared as required by the test specification, and the cable tested for ionization.

It will be observed that by reason of the hand cutting tool the tape is easily cut and removed from the underlying insulation layer. A clean cut is obtained around the circumference of the tape, and any nicks and scratches in the underlying insulation layer are avoided. This is particularly critical in conducting an ionization test, for otherwise a false ionization will Occur at the termination.

I claim:

1. A hand cutting tool comprising: a pair of elongate lever members, pivotally connected to each other intermediate their ends, to provide a pair of handles at one end thereof and a pair of arched upper and lower jaws on the ends thereof opposite their respective handles; and a spring wire, having a looped portion, connected at each end to the upper and lower jaws, whereby closing the handles separates the jaws and contracts the loop.

2. A hand cutting tool according to claim 1 including means 5 for adjusting the diameter of said looped portion.

3. A hand cutting tool according to claim 1 including means to bias said handles to a normally open position. 

1. A hand cutting tool comprising: a pair of elongate lever members, pivotally connected to each other intermediate their ends, to provide a pair of handles at one end thereof and a pair of arched upper and lower jaws on the ends thereof opposite their respective handles; and a spring wire, having a looped portion, connected at each end to the upper and lower jaws, whereby closing the handles separates the jaws and contracts the loop.
 2. A hand cutting tool according to claim 1 including means for adjusting the diameter of said looped portion.
 3. A hand cutting tool according to claim 1 including means to bias said handles to a normally open position. 